A conventionally known motor is provided with a rotor and a stator that is located on the outside of the rotor in the radial direction. The stator includes a stator core, insulators assembled with both axial-direction end surfaces of the stator core, respectively, and a coil wound around the stator core and the insulators. The stator core and the insulators are provided with a wrong assembly prevention mechanism that prevents the insulators from being wrongly assembled with the end surfaces of the stator core. The wrong assembly prevention mechanism prevents the wrong assembly of each insulator with respect to a circumferential position on each end surface of the stator core.
For example, Japanese Laid-open Patent Publication No. 2008-167516 discloses a conventional technology related to such a wrong assembly prevention mechanism. The wrong assembly prevention mechanism has a plurality of engagement holes provided to the stator core and a plurality of engagement claws provided to the insulators. The engagement claws engage the engagement holes, respectively. There are at least three engagement holes and engagement claws. All the engagement claws differ in shape from one another, while all the engagement holes differ in shape from one another correspondingly to the shapes of the engagement claws. Alternatively, the center angles between adjacent pairs of the engagement claws differ from one another, while the center angles between adjacent pairs of the engagement holes differ from one another correspondingly to the center angles between adjacent pairs of the engagement claws.
With the conventional technology, there are a plurality of engagement holes provided to the stator core and a plurality of engagement claws provided to the insulators that engage the engagement holes, respectively. When a winding wire is wound around the stator core and the insulators by a winding machine, a nozzle of the winding machine moves in the circumferential direction as passing through a slot upward or downward and moves to the next slot. At this time, if a circumferential force acts on the insulator due to the tension of the winding wire, the insulator is not displaced in the circumferential direction with respect to the stator core.
With the conventional technology, however, the stator core is provided with the engagement holes dedicated to engage the engagement claws, which increases the fabrication cost of the stator core.